Safari Autofill: Trigger password suggestions in Devise registration form

I have a very standard Rails 4 Application using Devise 3

I want to have the registration form to trigger password suggestions in the current (Mavericks) version of Safari:

iCloud Keychain is enabled and I get suggestions on other pages, just my form does not work with that for some reason.

I can't seem to figure out what exactly it takes to enable suggestions.

Here is the form that devise generates:

<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
  <div style="margin:0;padding:0;display:inline"><input name="utf8" type="hidden" value="&#x2713;" />
    <input name="authenticity_token" type="hidden" value="SKtqmi1L/BKcTE/Hvlvw1H3ZRH8nd2UNiNnVILuLS/E=" />
  </div>

  <div>
    <label for="user_email">Email</label><br />
    <input autofocus="autofocus" id="user_email" name="user[email]" type="email" value="" />
  </div>

  <div>
    <label for="user_password">Password</label><br />
    <input id="user_password" name="user[password]" type="password" />
  </div>

  <div>
    <label for="user_password_confirmation">Password confirmation</label><br />
    <input id="user_password_confirmation" name="user[password_confirmation]" type="password" />
  </div>

  <div><input name="commit" type="submit" value="Sign up" /></div>
</form>

• How do I need to change the form to trigger password suggestions

• are there any usable documentation anywhere about that feature?

Apple accepts new autocomplete properties: current-password and new-password

As outlined in a [PDF] guide made by Apple the autocomplete property now accepts set values to help with this issue.
See the spec here along with other valid values: https://html.spec.whatwg.org/multipage/forms.html#attr-fe-autocomplete-new-password

    <form method="post" action="/tests/4/register-submit" >
  <label>
    <div>Name</div>
    <input
      name="name"
      placeholder="name"
      autocomplete="name"
      type="text"
      pattern=".{4,}"
      title="Needs to be 4 characters long."
      required
    />
  </label>
  <label>
    <div>Username</div>
    <input
      name="username"
      placeholder="Username"
      type="text"
      autocomplete="username"
      pattern=".{4,}"
      title="Needs to be 4 characters long."
      required
    />
  </label>
  <label>
    <div>Password</div>
    <input
      name="password"
      placeholder="Password"
      type="password"
      autocomplete="new-password"
      required
    />
  </label>
  <input type="submit" value="Register" />
</form>

That code works due to the autocomplete="new-password" property used. autocomplete="current-password" is also possible for login forms.

This has been tested as working by the very helpful: @simevidas